In the relatively new technical field of plasmonics as a branch of nanophotonics, various efforts have been made in recent years to provide technical structures such as circuits in minimal area or to detect and analyze biological molecules or improve methods such as Raman spectroscopy or laser cell manipulation (e.g., Kocabas et al., Plasmonic Band Gap Structures for Surface-Enhanced Raman Scattering, Optics Express 16:12469-12477, 2008, and Baumgart et al., Off-Resonance Plasmonic Enhanced Femtosecond Laser Optoporation and Transfection of Cancer Cells, Biomaterials 33; 2345-2350, 2012).
A good overview of nanophotonic effects of surface plasmons, surface plasmon polaritons, photonic band gaps and the structuring of substrate surfaces is given in Barnes et al., Surface Plasmon Subwavelength Optics, Nature 424: 824-830, 2003, which is incorporated herein by reference.
In addition to a suitable excitation radiation, excitation of plasmons requires a structured, diffractive surface that is coated with a thin layer of gold or silver. Depending on the configuration of the structures on the surface, the achievable optical effects can be very finely tuned in coordination with the utilized excitation wavelength of excitation radiation. To obtain substrates with very fine structures, it has been suggested, for example, by Singh and Hillier, Surface Plasmon Resonance Enhanced Transmission of Light Through Gold-Coated Diffraction Gratings, Analytical Chemistry 80: 3803-3810, 2008, to use layers of writable DVDs (digital versatile discs). These layers of polycarbonate were provided with grooves with a spacing of about 1.5 μm and a height of about 160 nm and coated with gold. It was possible to use the substrate obtained in this way, for example, for detecting the thickness of ultrathin monolayers of alkanethiolates and antigen-antibody complex formation.